There is conventionally known a road surface markings map generating method that, while taking into consideration the positional offset of road surface images that arises when integrating data of plural lanes with respect to road surface images that are generated by affine transforming from measured positions and a video camera, integrates road surface images by using the path having the highest accuracy, in accordance with evaluated positional accuracy, as a reference path (Japanese Patent Application Laid-Open (JP-A) No. 2010-175756).